Interactive 3D Spectrum Analyzer Visualization for Windows Media Player

/*
 * Copyright (c) 2005-2009, Carlo McWhirter. All Rights Reserved.
 * Copyright (c) 2009, Hyteq Systems. All Rights Reserved.
 */

#include "stdafx.h"
#include <GL/gl.h>
#include <GL/glu.h>
//#include <GL/glaux.h>
#include "GLRenderContext.h"

BOOL GLRenderContext::m_bIsInitialized = FALSE;

/**
 * GLRenderContext constructor.
 * Creates an opengl rendering context. If multiple OpenGL rendering
 * contexts exist in an application, this class will make sure only
 * one rendering context is active at a time.
 */
GLRenderContext::GLRenderContext() :
	m_hRC( NULL )
{
}

/// Disassociates and frees the current device context
GLRenderContext::~GLRenderContext()
{
    if ( m_hRC )
    {
        wglMakeCurrent( NULL, NULL );
        wglDeleteContext( m_hRC );
    }
}

/// Called to prepare this class for rendering.
void GLRenderContext::Initialize(HDC hReferenceDC, BOOL bIsMemoryDC)
{
	if( m_bIsInitialized == FALSE )
	{
		m_bIsInitialized = TRUE;

		PIXELFORMATDESCRIPTOR pfd;
		ZeroMemory( &pfd, sizeof( pfd ) );
		pfd.nSize = sizeof( pfd );
		pfd.nVersion = 1;
		pfd.iPixelType = PFD_TYPE_RGBA;
		pfd.cColorBits = 32;
		pfd.cDepthBits = 16;
		pfd.iLayerType = PFD_MAIN_PLANE;

		if( bIsMemoryDC )
			pfd.dwFlags = PFD_DRAW_TO_BITMAP | PFD_SUPPORT_OPENGL | PFD_TYPE_RGBA;
		else
			pfd.dwFlags = PFD_DRAW_TO_WINDOW | PFD_SUPPORT_OPENGL | PFD_DOUBLEBUFFER | PFD_TYPE_RGBA;
		
		int format = ChoosePixelFormat( hReferenceDC, &pfd );
		SetPixelFormat( hReferenceDC, format, &pfd );

		m_hRC = wglCreateContext( hReferenceDC );
	}
}

/// Called to begin rendering.
void GLRenderContext::Begin(HDC hDC, BOOL bIsMemoryDC)
{
	if( m_bIsInitialized == FALSE )
		Initialize( hDC, bIsMemoryDC );

	wglMakeCurrent( hDC, m_hRC );

	glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
	glMatrixMode( GL_MODELVIEW );
    glLoadIdentity();
}

/// Called to end rendering.
void GLRenderContext::End(HDC hDC)
{
	SwapBuffers( hDC );
}

/// Checks whether the context has been initialized at least once.
BOOL GLRenderContext::IsInitialized()
{
	return m_bIsInitialized;
}